Drug interactions between Bactrim and ritonavir
| Results for the following 2 drugs: |
|---|
| Bactrim (sulfamethoxazole/trimethoprim) |
| ritonavir |
Interactions between your selected drugs
sulfamethoxazole ↔ ritonavir
Applies to:Bactrim (sulfamethoxazole/trimethoprim) and ritonavir
MONITOR: A disulfiram-like reaction has been reported in two patients who consumed alcohol while taking sulfamethoxazole-trimethoprim DS every 12 hours, although a causal relationship has not been established. The mechanism of interaction is unknown. Both ritonavir oral solution and lopinavir-ritonavir oral solution contain a substantial amount of alcohol (greater than 40% by volume), which, theoretically, can produce a disulfiram-like reaction when coadministered with sulfamethoxazole-trimethoprim. Pharmacokinetically, coadministration of ritonavir (500 mg every 12 hours) and sulfamethoxazole-trimethoprim (single 800mg-160 mg dose) has resulted in a 20% decrease in the area under the plasma concentration-time curve (AUC) of sulfamethoxazole and a 20% increase in the AUC of trimethoprim. The plasma level of ritonavir was not affected. These alterations are unlikely to be of clinical significance, thus dosage adjustments should not be necessary.
MANAGEMENT: Until further information is available, it may be advisable to avoid using ritonavir oral solution and lopinavir-ritonavir oral solution with sulfamethoxazole-trimethoprim. Patients who are prescribed the combination should be alerted to the potential of a disulfiram reaction, which may include symptoms such as flushing, throbbing in head and neck, throbbing headache, respiratory difficulty, nausea, vomiting, sweating, thirst, chest pain, palpitation, dyspnea, hyperventilation, tachycardia, hypotension, syncope, weakness, vertigo, blurred vision, and confusion.
trimethoprim ↔ ritonavir
Applies to:Bactrim (sulfamethoxazole/trimethoprim) and ritonavir
MONITOR: A disulfiram-like reaction has been reported in two patients who consumed alcohol while taking sulfamethoxazole-trimethoprim DS every 12 hours, although a causal relationship has not been established. The mechanism of interaction is unknown. Both ritonavir oral solution and lopinavir-ritonavir oral solution contain a substantial amount of alcohol (greater than 40% by volume), which, theoretically, can produce a disulfiram-like reaction when coadministered with sulfamethoxazole-trimethoprim. Pharmacokinetically, coadministration of ritonavir (500 mg every 12 hours) and sulfamethoxazole-trimethoprim (single 800mg-160 mg dose) has resulted in a 20% decrease in the area under the plasma concentration-time curve (AUC) of sulfamethoxazole and a 20% increase in the AUC of trimethoprim. The plasma level of ritonavir was not affected. These alterations are unlikely to be of clinical significance, thus dosage adjustments should not be necessary.
MANAGEMENT: Until further information is available, it may be advisable to avoid using ritonavir oral solution and lopinavir-ritonavir oral solution with sulfamethoxazole-trimethoprim. Patients who are prescribed the combination should be alerted to the potential of a disulfiram reaction, which may include symptoms such as flushing, throbbing in head and neck, throbbing headache, respiratory difficulty, nausea, vomiting, sweating, thirst, chest pain, palpitation, dyspnea, hyperventilation, tachycardia, hypotension, syncope, weakness, vertigo, blurred vision, and confusion.
See also...
Drug Interaction Classification
The classifications below are a guideline only. The relevance of a particular drug interaction to a specific patient is difficult to determine using this tool alone given the large number of variables that may apply.
| Major | Highly clinically significant. Avoid combinations; the risk of the interaction outweighs the benefit. |
| Moderate | Moderately clinically significant. Usually avoid combinations; use it only under special circumstances. |
| Minor | Minimally clinically significant. Minimize risk; assess risk and consider an alternative drug, take steps to circumvent the interaction risk and/or institute a monitoring plan. |
Do not stop taking any medications without consulting your healthcare provider.
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