Drug Safety Clinic

The Drug Safety Clinic is an outpatient clinic that provides comprehensive assessments of patients who have experienced possible adverse drug reactions. Our physicians evaluate, diagnose and help patients manage adverse drug reactions (including allergies), and provide clinical guidance regarding future drug therapy. For many patients, we perform drug-specific testing at the clinic.

Our multidisciplinary clinic is unique in Canada and recognized as a world leader in the field.

To be seen at the Drug Safety Clinic, patients require referrals from their physician or nurse practitioner.

Making an appointment

To access the Drug Safety Clinic you will need:

A referral from your doctor
Your doctor should fax this referral form to 416-480-5229.
A consultation appointment at our clinic
After we receive your doctor's referral, we will contact you to set up a consultation appointment. This will be an approximately 15-20 minute meeting with a physician specialist to review your medical history, including your reaction(s) to medications. Please bring a list of your current medications with you, as well as details about the reaction(s) you had and the names of suspected medications.

Plan to park for at least 1 hour for this appointment.
Testing appointment
During your consultation appointment, our doctor may determine that testing is appropriate for you. If this is the case, make a testing appointment with our Office Manager before you leave. Alternatively, we can call you to set up your appointment.

For testing, you will be at our clinic for approximately 6 hours from the scheduled time of your appointment (this includes time waiting for testing and any delays), then you will be discharged by our clinic physician.

Note: The consult and testing visit are rarely on the same day.
Desensitization appointment
In some cases, the clinic physician will recommend that you be desensitized to a medication you have reacted to in the past. For some desensitization protocols, our clinic pharmacist will call you to set an appointment to meet with you at our clinic.

Booking or rescheduling your appointment

Generally, we book appointments several months into the future. However, there may be cancellations, and you may call our Office Manager at 416-480-6100 x3061 to see if you can get an earlier appointment.

You will appreciate that we get many phone calls, so we ask you to limit your calls to once a week and speak directly with our Office Manager.

The best times to call are Mondays, Tuesdays and Thursdays from 7:00 a.m. to 9:00 a.m.
Please do not leave a voicemail. Our voicemail should only be used for cancelling appointments.

Cancelling your appointment

Should you need to cancel your appointment, please contact us at least 48 hours prior to the appointment or a $50 rebooking fee will be charged.

If you leave a voicemail or email us, please provide us with your name, phone number and the time of your appointment.

We appreciate your telling us in advance that you will not be coming to your appointment. Our clinic is very busy and we try and fill all openings!

Location and parking

How do I get there?

Map & directions to the hospital

The Drug Safety Clinic is located on the ground floor, in the U Wing, at UG 00, desk 1. Parking is available outside the U Wing.

How long should I park?

For consultation appointments, 1 hour is typically enough time.
Testing appointments take approximately 6 hours; consider taking advantage of the all-day parking rate.
Before coming into the clinic to start your testing, it is advisable to pay the full day rate and place the receipt on your dashboard.

Checking in for an appointment

What happens when I arrive?

Check in with our Office Manager at UG00 Desk 1.
Wait for your name to be called by our physician (for a consultation appointment) or our nurse (for drug testing).

As we share clinic space with other services, we ask our clients to find a seat down the hall from our clinic, not in the main seating area.
Following your consultation appointment with our clinic physician, if drug testing is recommended, please see our Office Manager to make an appointment for testing before you leave. Alternatively, we can call you to make a testing appointment.

Rarely, the consult and testing visit are on the same day.
If you are at the clinic for drug testing, learn more about drug testing appointments.

Are there washrooms nearby?

There are 2 washrooms, right next to our main office area, behind a wood panel.

To access, press on the large silver button outside the washroom. The door will open slowly, and will then close slowly. When you are inside the washroom and the door has closed, push the red button near the toilet to lock the door.

Where can I get food?

Food can be purchased from a number of locations throughout the hospital.
We encourage you to bring your own food, or purchase and bring it back with you to our clinic. For your safety, we prefer you remain in the clinic area as much as possible.

What happens at a drug testing appointment?

If you are at the clinic for drug testing, you may receive:
(click to learn more)

Skin testing

If you are uncomfortable or tend to feel faint around needles, please tell us before your testing so that we can help make the appointment easier for you.

Skin testing - prick and intradermal testing

For intradermal testing, a very small amount of the drug that you may be allergic to is gently injected under the skin with a needle, usually on the upper arm, creating a little bump. We circle the area with a pen, and if you are allergic to the drug, the bump will get bigger and redder and extend beyond the marked circle.

With prick testing, a small amount of the drug that you may be allergic to is placed on your skin, usually your lower arm. The skin is then gently pricked. If you are allergic to the drug, you will get a large bump and redness where the skin is pricked.

For most drugs, we use intradermal testing, not prick testing. However, everyone who has skin testing will also receive prick testing with histamine and salt water (normal saline), usually on the forearm. The histamine/salt water test does not tell us anything about your allergy. It simply is used as a control to help us make sure that the intradermal testing is valid.

We use intradermal skin testing to test for certain drugs, including the following:

Contrast dyes
Corticosteroids
General anesthetics
Local anesthetics
Metronidazole (e.g., Flagyl®)
Penicillins
Quinolones (e.g., ciprofloxacin, levofloxacin, moxifloxacin)
Sulfonamide antibiotics

For skin testing, we will call you back after 30-40 minutes to read the test results. Depending on these results, and the medication we are testing, we may give you a drug challenge, after which we will monitor you for approximately 4 hours, then you will be discharged by our physician.

Skin testing followed by a drug challenge

Intradermal testing plus challenge dose

Where available, a challenge dose of medication is used in addition to skin testing, usually if the skin test results are negative.

Following the skin test, you will receive a regular dose of the drug (by mouth, injection, inhalation, nasal spray or as eyedrops – this depends on how the drug is usually given). In some cases, you will receive two doses of the drug. You will then be observed under the care of our clinic physician for approximately 4 hours after the dose, before being discharged.

Drug challenge only

Challenge dose alone

A challenge dose is also used when skin testing is not appropriate or available. In some cases, you will just receive a regular dose of a drug (sometimes two doses). Depending on the drug, this may be by mouth, injection, inhalation, nasal spray or as eyedrops. You will be observed under the care of our clinic physician for approximately 4 to 5 hours after the dose.

For example, we administer challenge doses of the following drugs:

Non-steroidal anti-inflammatory drugs (NSAIDs) like aspirin, ibuprofen or naproxen
Opioids (e.g., codeine, morphine, oxycodone)
Inhaled asthma medications (e.g., salbutamol)
… and many other medications.

Desensitization protocol

Desensitization

In some cases, the clinic physician will recommend that you be desensitized to a medication you have reacted to in the past. By introducing the medication gradually, starting with an extremely low dose and building up to a therapeutic dose over a set time period, it is possible to induce a temporary tolerance to that medication. This tolerance lasts as long as you take the medication as prescribed, usually at least once daily.

Depending on the drug, desensitizations may be conducted at our clinic (over a few hours) or our physicians may prescribe a protocol for you to follow at home (over a period of a few weeks).

Desensitization in our clinic

In some cases, we will prepare a desensitization protocol for you, which will be given at our clinic. For example, for desensitization to low-dose aspirin, you will come to our clinic to receive a dose of aspirin every 30 minutes, over an approximately 3-hour period, to a final dose of 81 mg (one baby aspirin). We will observe you at the clinic for an additional 2-3 hours.

Desensitization at home

Sometimes, our physician will prescribe the desensitization protocol for you to follow at home, over a period of up to a few weeks. Sunnybrook’s outpatient pharmacy will contact you for your drug plan information, and you will be billed for the prescription. Our pharmacy manufacturing team will prepare the medication in doses required for the protocol, starting with no medication (placebo) or very low doses and building up to a target therapeutic dose.

Once the prescription is ready, we will telephone you to make an appointment with our pharmacist, where you will review the protocol in detail and receive the medication. We will follow up with you during and after the protocol.

For skin testing, we will call you back after 30-40 minutes to read the test results, and depending on these results, may give you a drug challenge, after which we ask you to wait for 3-4 hours so we can monitor you, then you will be discharged by our physician.
For the one-dose drug challenge, we ask you to wait for several hours so we can monitor you, then you will be discharged by our physician.
For the two-dose drug challenge, we will give you an oral dose of a medication, then call you back after 30-60 minutes to administer a second dose. We then ask you to wait for several hours so we can monitor you, then you will be discharged by our physician.
If you have had drug testing, our clinic physician will discharge you at the end of the day, generally 5 to 6 hours after your appointment time.

Please do not ask to be seen/discharged earlier.

If you cannot stay for this period of observation, we will not be able to send a report to your physician regarding your final testing results.

Possible reactions to testing

Reactions at the clinic

Local reactions, which usually present as redness and swelling at the injection site, can occur either immediately or several hours or even several days after skin testing.

Systemic (whole body) reactions, are less common than local reactions. Systemic reactions are usually mild and respond rapidly to medications, such as antihistamines. Symptoms can include nasal congestion, hives or sneezing. A serious systemic reaction, called anaphylaxis, may occur extremely rarely after skin testing or oral challenge. Symptoms of an anaphylactic reaction include hives, swelling, wheezing, shortness of breath, nausea, dizziness and other symptoms.

The staff at the Drug Safety Clinic is trained to monitor and treat such reactions.

Reactions after you leave our clinic

Although rare, it is possible for patients to have a reaction after leaving our clinic. You should be alert for any unusual symptoms that might occur up to 48 hours later. These symptoms could be related to the medication you received at our clinic.

Symptoms may include:

Local reactions: Bruising, redness, swelling or irritation at the site you received any injections is normal and common. Local reactions should not result in a more serious reaction. Increasing redness or swelling over the next few days is unusual.
Systemic reactions: These reactions are less common than local reactions, but may include rash, swelling, fever, mucosal lesions (e.g., ulcers in the mouth), vomiting or diarrhea.

In the unlikely event you have a reaction after you leave our clinic, if the symptoms are severe or getting worse, see your physician or go to the nearest walk-in clinic or hospital Emergency Department to be assessed and treated.

Keep us informed

Please telephone or email us to tell us about any symptoms you had after you left our clinic. If possible, take digital photographs of the reaction and email these to us with your name, the date you were tested at our clinic, the date you took the photo(s) and a detailed description of the reaction, including how you treated it. We will record this in your file and, where appropriate, we will call you back and/or write a further letter to your referring physician.

Preparing for a testing appointment

How should I dress?

Dress in layers, as it may be hot/cold in the clinic area, and temperatures may change throughout the day.
Wear a loose, short-sleeved top made of stretchy fabric that is easy to roll up, as skin tests are given in the upper arm area very near the shoulder. Dark colours are preferable, as some patients may bleed slightly at the injection site.
Do not wear any lotion on your arms or shoulders, as this could make it more difficult to administer skin testing.
Do not wear perfume or scented products, as Sunnybrook is a fragrance-free hospital.

Can I take my prescription, non-prescription and alternative medications before I come to the clinic?

Always check in advance of your testing appointment. During your consultation appointment, this information will be provided to you.

Generally, you can take your usual medications unless we have asked you to stop them on the day of testing, or for a few days before the testing. Everyone who makes a testing appointment receives a handout that sets out several medications that may interfere with testing.

To be certain, provide a copy of the Drug Safety Clinic handout to your physician or community pharmacist and ask them to review your medications, or check with our clinic our pharmacist, Jackie Campbell at 416-480-6765 well in advance of your appointment.

Do I need to discontinue any medication before testing?

Antihistamines or drugs that have antihistamine properties can interfere with the skin test results. If you are taking an antihistamine, you will be advised to stop the medication at least 3 to 5 days before coming in for your testing.

Examples of these drugs (and common brand names) include:

amitriptyline (Elavil)
brompheniramine (Dimetapp)
cetirizine (Reactine)
chlorpheniramine (Triaminic)
cyproheptadine (Periactin)
desloratadine (Aerius)
dexbrompheniramine (Drixoral)
dimenhydrinate (Gravol)
diphenhydramine (Benadryl)
doxepin (Sinequan)
doxylamine (Nighttime, NyQuil)
fexofenadine (Allegra)
hydroxyzine (Atarax)
loratadine (Claritin)
maprotiline (Ludiomil)
mirtazapine (Remeron)
promethazine (Histantil, Phenergan)
trimipramine (Surmontil)
triprolidine (Actifed)

This list does not contain all of the products available in Canada. Check with your pharmacist or doctor, or call the Drug Safety Clinic, if you have any questions.

If you are on a beta-blocker or an ACE-inhibitor (medications for your heart or for high blood pressure), you may be asked to stop the drug for one to two days before coming in for testing. Your doctor at the Drug Safety Clinic will discuss whether or not you need to discontinue these medications.

All other medication, including asthma puffers and prednisone, should not be stopped.

Can I eat before or during the clinic?

Absolutely! Eat or drink as usual before and during the clinic. Eat a regular breakfast before coming for testing and bring a snack/lunch with you. Food can also be purchased from a number of locations throughout the hospital.

We encourage you to bring your own food, or purchase and bring it back with you to our clinic. For your safety, we prefer you remain in the clinic area as much as possible so we can monitor you.

What should I bring?

You are at our clinic to be tested for drug sensitivity and part of this testing includes being available to us so we can monitor you. Accordingly, we want you to remain in the clinic area as much as possible for an approximate 6 hour timeframe.

We encourage you to be prepared to spend the day with us. Consider bringing:

Food and drinks with you from home.
There are cafeterias/coffee shops in the hospital, but we prefer if you stay in the clinic area during your testing period.
A good book
iPad or laptop: Sunnybrook has free wifi

Can I bring a family member with me?

Our clinic space is quite limited, and is used by the many clients we see on testing days as well as clients from other clinics. Unless you need assistance, we encourage you to come on your own.

Out of town patients

If you are travelling from out of town to attend a drug testing appointment, you may be eligible to have some of your travel costs reimbursed through the Northern Health Travel Grant Program.

Click to access travel grant forms on the Government of Ontario website.

If you qualify for this program, please bring a completed form with you and speak with our Office Manager who will fill in our clinic information for you.

Code of courtesy

Please be patient with us. We have a long waiting list and try to see as many patients as we can on clinic days. The 5-6 hour appointment time that we give you includes time taken where we run into delays that we cannot predict (e.g., dealing with complex patient cases, patient reactions or anxiety). Please appreciate that we cannot accurately predict all delays, but we are doing our best to provide service to you.

As we share clinic space with other services, we ask our clients to find a seat down the hall from our clinic, not in the main seating area.

If you can't make your appointment time, we appreciate your telling us in advance. Our clinic is very busy and we try and fill all openings!
Should you need to cancel your appointment, please contact us at least 48 hours prior to the appointment or a $50 rebooking fee will be charged.

Please do not talk loudly on cell phones. This can disturb fellow clinic patients, and several people have their offices very close to our clinic.

If you have any concerns, or want to tell us about your experience at our clinic, please let us know, or call 416-480-6765